Conventional methods of transferring audio information, or programs, from a prerecorded "master magnetic" tape require the compilation of an "edited" master magnetic tape. Generally, the master magnetic tape is quarter-inch tape having audio signals recorded thereon in two-track stereo format. The audio signals are reproduced from this master magnetic tape and are edited onto the edited master in a desired sequence or arrangement such as, for example, four equal length programs for eight-track recordings or two equal length programs for four-track recording. The edited master magnetic tape then is reproduced by a tape reproduction machine, and suitable electronic devices, such as equalizers, limiters, noise reducers, and the like, process the reproduced signals to adjust the quality of the audio information.
The processed audio signals then are recorded onto a production master magnetic tape at normal reproducing speed.
Conventional production master tapes are either one-half or one-inch magnetic tapes; and are driven in a playback device known as a loop bin, wherein the processed audio signals recorded thereon are reproduced for recording onto yet another recording medium such as desired end-use magnetic tapes. The production master tape, having its respective ends spliced together in a continuous loop configuration is played back at high speed, such as on the order of between sixteen and sixty-four times normal reproducing speed. Hence, the information on the production master tape can be transferred onto blank magnetic tape by one or more high speed duplication recorders, known as "slaves", each of which ordinarily produces between twenty and sixty copies of the audio program on one continuous roll of blank tape.
In order to locate the beginning and end of each complete program a low frequency "cue" tone is recorded on the duplicated, or "slaved" recording medium as the splice on the production master tape passes a sensing device. However, the splice presents a physically weak structure which is susceptible of breakage after only a relatively few cycles of the production master tape. Also, the duplicating speeds at which the production master tape can be driven are limited by the relatively fragile nature thereof. Futhermore, while the production master tape is reproduced at high speed in the loop bin, a twist or wrinkle in the tape often develops, resulting in damage or destruction of the production master. As a result, numerous production master tapes must be compiled at considerable effort and expense in order to produce the desired number of end-use tapes. Additionally, use of an intermediate production master tape results in loss of fidelity from the original master tape. Detrimental effects in noise, distortion, degraded frequency response, poor phase response, drop outs, undesirable wow and flutter, and the like, also may result when a production master tape is compiled.